Law of Conservation of Mass/Transcript
Transcript Text reads: The Mysteries of Life with Tim & Moby. A man, Tim, is standing next to a robot, Moby, in a laboratory. There are beakers on a countertop. Moby is wearing a white lab coat and protective glasses. Moby is holding a test tube containing a blue liquid. He is studying a dish containing a chunk of mineral in a dish in front of him. Tim is wearing a white tee shirt with a blue cube emblazoned in the center. TIM: Still trying to turn lead into gold? Moby pours most of the contents of his test tube onto the mineral. MOBY: Beep Moby blinks a few times as he studies the mineral carefully. It is now sitting in a shallow pool of blue liquid. It has not changed. Tim picks up a beaker containing more of the blue liquid. He studies the contents. TIM: Hey, isn’t this just food coloring? Tim holds up a letter and reads it. TIM: Dear Tim & Moby, What is the law of conservation of mass? And what happens if you break it? I Love You. Marie-Ann. Tim blushes. TIM: Um. Thanks. You, uh … you can’t actually break the law of conservation of mass. It’s not that kind of law. In science, a law is a generalization about how the physical universe works. Tim and Moby are shown standing side by side in the laboratory. A drawing shows a man studying a chalkboard. The board shows a cube and various mathematical expressions. The man is scratching his head. TIM: The law of conservation of mass basically means that substances can’t be created or destroyed. A drawing shows a toy robot standing next to a green gem and a puddle of water beneath them. The pair of figures is surrounded by the “no” symbol: a red circle with a red slash through it. The water, robot, and the gem disappear, leaving a white background inside the “no” symbol. TIM: Or, in the language of chemistry, the mass of the reactants in a chemical reaction always equals the mass of the products. An animation shows five blue objects with plus signs between them. The objects appear to be parts of a plane: the propeller, the body, the wings, and the fins. The object turns white. To the right of these objects is an equal sign and the image of a completed plane. It seems to be made up of the parts shown on the left—first shown in blue, then white. The view switches back to Moby and Tim in the laboratory. MOBY: Beep? TIM: Yeah, let’s take a look at some of those terms. First of all, mass is the amount of matter a substance has. An image of Tim is shown in a solid brown background. Tim’s clothes and facial details disappear, leaving only a white outline of Tim. A caption reads: “mass.” TIM: Unlike weight, which changes depending on how much gravity is present, mass stays the same no matter where you are. An animation shows two views of Tim. In one, Tim is standing on the Earth. In the other, Tim is standing on the moon. A starry sky can be seen in the background. Red arrows pointing down represent the pull of gravity. The arrow in the Earth scene is larger than the arrow in the moon scene. A caption reads: “weight.” Then both images of Tim turn into plain white outlines. The two outlines have exactly the same size and shape. TIM: So, although you might have different weights on, say, the earth and the moon, your mass stays the same. Back in the laboratory, Tim and Moby are shown side by side. Tim is speaking. TIM: We're good? MOBY: Beep TIM: Okay, next, a chemical reaction is when two or more molecules interact to form different molecules. For example: hydrogen and oxygen react to form dihydrogen monoxide, or water. An animation shows three cartoon-face atoms. One large one has a red cap reading “Upper O.” The other two small ones are identical and have blue caps reading “Upper H.” The two hydrogen atoms bump into the oxygen atom. A flash appears, and the two hydrogen atoms move away. However, now there is a red line connecting each hydrogen atom with the oxygen atom. A caption reads: “Upper H subscript 2 Upper O.” A glass of water then appears. TIM: In that reaction, hydrogen and oxygen are the reactants, the substances that are around at the beginning of a chemical reaction. The screen is replaced with a drawing of just the three atoms standing by themselves. A caption reads: “reactants.” TIM: And the water is the product, or what’s around after a chemical reaction takes place. The glass of water appears on the screen. A caption reads: "product.” TIM: The law of conservation of mass states that the mass of the reactants must equal the mass of the products. The three atoms turn gray. The glass of water turns gray. A plus sign appears between the atoms. An equal sign appears between the atoms and the glass. The gray areas seem to have about the same area. The scene returns to Tim and Moby in the laboratory. MOBY: Beep? TIM: Well, I know it seems kind of obvious. Stuff can’t just … disappear, or appear out of thin air. And before the law was actually written down, people had been proposing the idea for centuries. A drawing shows five people. Each raises his hand in turn. Their clothing and hairstyles indicate that they come from different countries and different periods of time. TIM: Probably the first person to propose the law in a scientific way was Mikhail Lomonosov in Russia, in about 1748. A sketch of Mikhail Lomonosov appears. A close-up of Tim appears. TIM: But his work wasn’t known outside of Russia until much later. In the 1780s, a French guy named Antoine Lavoisier came up with a more precise description of how the law works, so we usually think of him as its discoverer. A sketch of Antoine Lavoisier appears. The view returns to Moby and then Tim. MOBY: Beep? TIM: Yeah, sure it’s useful! If you only know part of the mass of the chemicals in a reaction, you can use the law of conservation of mass to figure out the rest. Let’s say you have 4 grams of hydrogen and 32 grams of oxygen. An animation shows two gaseous clouds. One is smaller and labeled as being 4 grams of hydrogen; the other is larger and is labeled as being 32 grams of oxygen. TIM: By adding the masses of the reactants together, you can figure out the mass of the product—36 grams of water. A plus sign appears between the two clouds. Below them, a glass appears, labeled as being 36 grams of water. TIM: You can do it backwards, too. A drawing of a chalkboard appears. TIM: Potassium oxide combines with water to form potassium hydroxide. Four atoms appear on the board. The first is labeled “Upper K subscript 2 Upper O.” The second is labeled “Upper H subscript 2 Upper O.” The third and fourth, a little further off to the side, are identical and are both labeled “Upper K Upper O Upper H.” Underneath the atoms, a chemical equation appears, reading: “Upper K subscript 2 Upper O plus Upper H subscript 2 Upper O 2 right-arrow 2 Upper K Upper O Upper H.” TIM: So, let’s say you have 18 grams of water. The text “question mark plus 18 g” appears below the water atom. TIM: How much potassium oxide do you need to get 112 grams of potassium hydroxide? An arrow pointing to the right from 18g to 112g appears with the arrow and 112g. The equation reads: question mark plus 18 g right-arrow 112 g. TIM: Yup, you need 94 grams of potassium oxide. The question mark is replaced by flashing text that reads: “94 g.” The equation reads: 94 g plus 18 g right-arrow 112 g. The scene returns to Tim and Moby in the laboratory. MOBY: Beep? TIM: Yeah, you didn’t use enough. It takes 250 grams of blue food coloring to turn lead into gold. MOBY: Beep! Moby frowns. TIM: Yeah … I'm … I'm joking. Category:BrainPOP Transcripts